Let-off mechanism for looms



July 31, 1923- R. H. GILFILLAN LET-OFF MECHANISM FOR LOOMS 3 Sheets-Sheet 1 Filed Aug. 18 1921 Wam" /6 .l L

July 31 R. H. GILFILLAN LET-OFF MECHANISM FOR LOOMS Filed Aug. 18, 1921 3 Sheets-Sheet 2 M Q Q N 2 I 1 am MN July 31, 1923 R. H. GILFILLAN LETOFF MECHANISM FOR LOOMS Filed Aug. 18, 1921 3 Sheets-Sheet 3 Q N. Q Q Q Q R I, g N Mm fi W ,F i mm: 3 F N. a in nu N M k fl R Patent July 31, 1923..

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LET-OFF MECHANISM FOR LOOKS.

Application filed August 18, 1921. Serial No. 498,291.

'To allwk'omit may concern:

Be it known that 1, 'ROBERT H. GIrJ LLAN, a citizen of the United States, residing at New Holland, in the county of Lancaster and State of Pennsylvania, have invented certain new and useful Improvements in Let-Ofi' Mechanism for Looms; and I do hereby declare the followingto be a full, clear, andexact descri such as will enable 0t are skilled in the art to which it a'ppertains to make and use the same.

This invention relates to tension devices for use in yarn supplying mechanisms for power looms and more particularly to mechanism for letting ed and taking up the warp so as to maintaln the proper tension thereon during the operation of weaving,

The common method of tenslonln the warp threads of looms is by means 0 friction devices, such for example as a strap wound around the warp beam and havm weights suspended from its lower on. When for any reason an ad ustment is necessary the operator is compelled to go behind the loom and lift the welght and this is extremely objectionable as the operators are often girls, who are unable to stand up under the strain of this back breaking task.

One object of the invention is to overcome the objections above noted and to provide a device of the character referred to consisting of few parts and with pawl and ratchet mechanism capable of letting-0d the thread an almost infinitesimal amount or as much as is desired, and better and more generally applicable for various grades and of the loom and lifting the weight when making an adjustment, providing means operable from the front of the loom whereby the let-ofi motion may be thrown out of gear and the tension on the warpreleased to enable the operator to asick out imperfections or make necessary justments.

The invention will first be hereinafter more particularly described, with reference to the accompanying drawings, which are to be taken as a part of this specification,

and then pointed out in end of the description.

In said drawings, Fig. 1 is a side elevation, partly broken the claims at the ion of the invention,

away, of a 100m showing my improvements ap lied thereto;

1g. 2 1s a rear view partly in section,

showing the warp beam, whip roll and Fig. 4 is a detall fragmentary side view of the let-ofi' mechanism; and

Fig. 5 is a detail view :at right angles to F ifi. 4.

eferring to said drawings in which the same reference numerals are used to denote corresponding parts in difi'erent views, the numeral 1 designates generally the frame of a loom as ordmarily constructed'provided with the usual lay and operating mechanism which it is unnecessary to describe,and hav ing the usual main driving shaft 2 journaled in suitable bearings at a point slightly rearwardly of the middle of the frame. Parallel to shaft 2 and at a point near the rear of the machine is mounted a warp beam shaft 3, carrying a warp beam 35. A whip-roll d is mounted adjacent the rear end of the frame 1 on the arms 501 a air of hell crank levers pivoted at 6 and h tending toward the front end of the loom. Suspended by a cord or other suitable means from each of the forward extensions 7 of the arms 5 are weight-members W consistmg of one or more weights, which serve to maintaintension on the yarnas it is unwound from the warp beam 35 and passes around the whip-roll 4 which is revolubly mounted on the arms 5. On one side of the machine, attached tothe end of one of the arms 5 and movable therewith is a dependaving arms ex-.

ing rod or bar 8. having adjustably connected thereto at its lower end one end of a hori zontal bar 10, by means of an oblong slot 9 in the bar 10, and a pin or screw 8 protruding from the bar 8 through said slot.

An adjusting screw. or-bolt 11 is also carried.

in one end of the slot 9, and may be moved to-shorten the reciprocatory motion of the pin 8 in theslot 9. In the o posits end of arm 10 is a pin 12, which is a apted to move in an arcuate slot 13 in a lever 14, which ispin 12 also passes throu h ak l8, which re connected by means 0 another link 19 to the short a of a bell crank lever 22, the long a 21 of which carries a plurality of actuating pawls' 22, adapted for engagement with a ratchet wheel 29 mounted upon a horizontal shaft 30, extending lengthwise of the loom; The Wis 22 are preferably constructed of di' rerent lengths-in order that the ratchet wheel may be moved\ as much as one notch or tooth or as little as one-third of one notch. Thus it will be seen that the let-0d motion isextremely delicate in its 0 eration. The horizontal shaft 30 isrovided at the front with a hand whee 31 and at the rear with a worm 32 which intermeshes with a gear 33 on the warp beam shaft 3. A rod 23 having a cut-away portion or recess 24: therein projects through a socket 25 attached to or integral with the bell crank lever 21, and is connected, by means of a link 26, to a lever 27, which is ivoted at28 at or'near the front of the com frame 1.

In the process of weaving, after each throw of the shuttle the lay L heats up, and the cloth be, (not shown) is operated to take u the woven fabric. The tension thus exerts causes the arms,-57 to move about the pivots 6 and slightly raise the weight W. This movement is transmitted through lever 8 to arm 10, which actuates the pin 12 so as to vary its position in the slot 13, and the operating lever it, being oscillated or raised by the rotation of the shaft 2 so as to cause the cam 17 thereon to engage said lever, im-

parts a recipnocatory movement to the links 18 and 19 and room hell crank lever 20 to actuate the pawls 22. This lever 20 will be given a longer or shorter stroke depending upon the position of the pin 12 in the slot 13 so that the pawls engaging the teeth of the ratchet wheel 29 on the shaft 30 will rotate the same inteittently etc by step, and impart a corresponding step y step movement to the warp beam 35, so that the warp will be automatically let-ofi as needed. The letod therefore depends upon, and its adjustment is automatically governed by the tensionof the threads between the cloth beam and the warp beam.

In the operation of the loom the yarn is unwound from the warp beam, passes over the whip-roll, through the heddles and reed and finally is wound around the cloth beam.,/

The whip-roll vibrates in response to the unease"? In normal 0 erative position the pawls 22 are opposite t e recess or cut-away portion 24 in the rod 23. Should it be necessary to pick out a defective thread, the operator will grasp the hand lever 27' and move it so as to cause that portion of the rod 23 forward of the cut-away ortion 2st to engage the pawls 22 and with raw them from engagement with the ratchet wheel 29. The operator may then by turning hand wheel 31 rotate shaft 30 and let back on the warp beam, by means of the worm 32 and gear 33.

From the foregoing description it will be readily understood that my invention provides let-0d mechanism which is simple in Gil construction and efiicient in o oration, the warp threads bein automatica y and prop- Oil ate my let-0d motion as the warp is tensioned by weights to the required amount for each particular quality or grade of being woven and remains-the same laugh-- out the entire length of the warp.

Having thus described my invention, what I claim as new and desire to secure by Let tors-Patent is:

1. In a m, a warp beam, a shaft extending lengthwise of the loom geared to the warp manna handwheel on said shaft at the front of the loom, a ratchet on the shaft between the handwheel and the warp beam for letting 0d, a lever pivoted on the shaft, pawls on the lever en aging the ratchet, a cam slidably mounte on said lever and adapted to render said pawls inoperative, and a hand lever at the front of the loom connected to said cam, substantially as set forth.

2. In a loom, a warp beam, a shaft'extending lengthwise of the loom geared to the warp beam, a handwheel on said shaft at the. front of the. loom, a shaft extending across the loom, connections between said shafts for normally driving the warp beam in a direction to let off the wa and means operable from the front of t e loom for disabling said driving connections whereby the warp-beam may be turned back by means of said handwheel, substantially as set forth.

3. In a loom, a warp beam, a whip-roll, a shaft geared to the warp beam, means for driving the shaft with a variable stroke in cluding a lever, means for operating the Mill llll

'llii ratchet on the shaft, a pawl therefor, a lever with a constant stroke, a link movably connected to the lever for operating the pawl with a variable stroke, and means controlled by the movement of the whip-roll for determining the relation of the link to the lever, substantially as set forth.

4. In a loom, a warp beam, a whip-roll, a shaft geared to the warp beam, means for driving the shaft with a variable stroke including a lever, means for operating the lever with a constant stroke, sa1d lever having a longitudinal slot, a link operated by the lever, said link having a projection movable in the slot to vary the stroke of the link, connections from the link to said shaft for operating the same, an arm swinging with the whip-roll, and an adjustable lost motion connection between said arm and the projection on said link, substantially as set forth.

5. In a loom, a warp beani, a whip-roll, a shaft extending lengthwise of the loom geared to the Warp beam, a handwheel on said shaft at the front of the loom, a ratchet on the shaft between the handwheel and the warp beam for letting ofi, a lever pivoted on the shaft,'pawls on the lever engagin the ratchet, a cam slidably mounted on sai lever adapted to render said pawls inoperative, a hand lever at the front of the loom connected to said cam, an oscillatory lever beneath said ratchet having a longitudinal slot, a link attached to the pawl lever and having a projection engaging the slot, an arm swinging with the whip-roll, and a link attached to said projection and adjustably' connected to said swinging arm for varying the point of connect-ion of said link and said oscillatory lever to vary the action of the pawl and ratchet mechanism, substantially as set forth.

In testimony whereof I aflix my signature in the presence of two witnesses.

ROBERT H. GILFILLAN. Witnesses:

WM. G. Grumman, J OHN F. Horn. 

